| Back to News & Notices | Sales Support Locations | Company Profile | Product Directory |
|
Do you have problems getting your NTSC color cameras to relate to IRIG B? The ITS Model 6040 VMEbus IRIG/NTSC Synchronizer or the Model 6140 may solve your problem. Just apply your IRIG B serial time signal to this board and out comes true NTSC sync signals (59.94Hz). Both composite and horizontal/vertical sync is produced that is precisely synchronized with the output of any other 6040 that is tied to the same IRIG signal, just as you used to do with monochrome RS170. Although the synchronization function is independent of the bus, lock status and IRIG time may be read via the bus. "How does it do that?", you may ask. Well it so happens that if an IRIG time signal and an NTSC video signal are coincident at some specified reference time, then they will return to coincidence every 1001 milliseconds. The magic frequency is 31.5MHz so the 6040 produces this frequency and phase locks it with the applied 1KHz IRIG carrier. The result is then used to generate the composite video. We now have an NTSC video signal that is phase locked to IRIG, but that doesn't do much good unless we know when the frame starts. After all, the reason that we're going through all this trouble is so we can have all of the cameras driven by the common IRIG signal be frame synchronized. So the next step is to decode the IRIG time and using Midnight, January 1st as the absolute reference, calculate when the next 1001ms interval should occur. All this work is done by an on-board processor. So now, at the calculated interval, the sync frame counters are reset to the beginning of the first field vertical sync interval. Now we're in sync, and every 1001ms the 6040 makes sure. If the IRIG is lost or corrupted in any way, the interval reset is disabled to prevent the NTSC sync frame from being resynchronized erroneously. The 6040 continues to produce the composite sync from the internal clock. If the 6040 processor decides that the next interval update is incorrect, it will assume an error has occurred and restart it's locking procedure. So there we are, all your color cameras are as one. By the way, If you still have a requirement to synchronize your monochrome cameras, we have the 6040A IRIG/RS-170 synchronizer. It has all the features of the 6040 except it produces a standard 525/60 RS-170 video sync frame. If you have CCIR or PAL video, you're not forgotten. The Model 6036 IRIG/CCIR Synchronizer produces 50/625 composite and horizontal/vertical sync, synchronized with IRIG. Otherwise it also has all the features of the 6040. All ITS VMEbus boards are dual height 6U, occupy one slot (0.8 inch) and require 5V and +/-12V power. Need more information? Give us a call at (818) 886-2034, or Email at info@itsamerica.com
Copyright © 1998, Instrumentation Technology Systems
|